Answer:
The correct answer is letter "B": topic.
Explanation:
Topics are the central theme of studies, researches, books or speeches. A topic represents the main idea that is intended to be provided and from where all additional points of view depart. Usually, authors expose topics that are of their interest and that could be of interest to others.
The principal structural characters effected were in the postcranial anatomy, especially in the skeletal and muscular systems.
Organic compounds are those
compounds that are carbon based. Most carbon based compounds are organic.
Organic compounds are composed of gas, liquid and other solid compounds,
this all contains carbon. Methane is one of the simplest organic compounds.
Organic compound are classified into various ways. The natural compounds
that usually came from the plants and animals, the biotechnology came from
the industrially manufactured organisms like yeast and bacteria, and the
synthetic compounds produced from other compounds, it does not occur
naturally.